Role of magnetic resonance imaging in the diagnosis of cervical lymph node metastasis with unknown primary

Swapnali Y Chaudhary; Varsha B Aher; Rajendra S Birangane

doi:10.4103/2321-3841.170620

CASE REPORT

Year : 2015 | Volume : 3 | Issue : 3 | Page : 97-100

Role of magnetic resonance imaging in the diagnosis of cervical lymph node metastasis with unknown primary

Swapnali Y Chaudhary, Varsha B Aher, Rajendra S Birangane
Department of Oral Medicine and Radiology, Pandit Deendayal Upadhyay Dental College, Sholapur, Maharashtra, India

Date of Web Publication

27-Nov-2015

Correspondence Address:
Dr. Varsha B Aher
B-5 Mathura Villa CHS Ltd., Plot 147-148, Sector-21, Nerul (East), Navi Mumbai - 400 706, Maharashtra
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/2321-3841.170620

Abstract

Visual inspection and bimanual palpation are the cornerstones of diagnosis of diseases of the oral cavity. Clinical examination, however, could underestimate the deep spread of tumors and thereby the submucosal extent and limiting accurate pretreatment staging of disease. Imaging provides additional staging information such as precise location and local extent of the tumor which help in the selection of most effective treatment option and extent of surgical excision. Magnetic resonance imaging (MRI) offers an excellent aid for the evaluation of tumors of the oral cavity due to direct visualization of soft tissue in multiple planes. An interesting case of a 35-year-old male patient with extensive lymph nodal mass involving left side of the neck with limited mouth opening is reported. MRI was very helpful in locating the site of primary neoplastic mass along with providing the exact extent of the tumor and its effect on adjacent vital structures.

Keywords: Cervical lymph node metastasis, magnetic resonance imaging, tongue cancer

How to cite this article:
Chaudhary SY, Aher VB, Birangane RS. Role of magnetic resonance imaging in the diagnosis of cervical lymph node metastasis with unknown primary. J Oral Maxillofac Radiol 2015;3:97-100

How to cite this URL:
Chaudhary SY, Aher VB, Birangane RS. Role of magnetic resonance imaging in the diagnosis of cervical lymph node metastasis with unknown primary. J Oral Maxillofac Radiol [serial online] 2015 [cited 2023 Apr 2];3:97-100. Available from: https://www.joomr.org/text.asp?2015/3/3/97/170620

Introduction

The examination of patients with neoplasms of the head and neck has evolved significantly in the past decade. Although physical examination and endoscopy remain important diagnostic techniques, cross-sectional imaging has had an increasingly important role in both initial evaluation and follow-up care. Computed tomography and magnetic resonance imaging (MRI) complements the physical and endoscopic examinations, giving the surgeon, information about the extent of the lesion and associated adenopathy, thus, contributing to important treatment decisions. ^[1] In the following article, an interesting case is presented wherein intraoral examination of the patient was not possible due to limited mouth opening but the lymph nodal mass seen on left side of neck was suggestive of presence of neoplastic growth in the oral cavity.

Case Report

A 35-year-old male patient reported to the outpatient department of Government Dental College and Hospital, Mumbai, with the complaint of swelling in the left angle of mandible region [Figure 1] since 1-year and reduced mouth opening [Figure 2] for 15 days. His medical and dental history was noncontributory. He was a farmer by occupation and was illiterate. He had a habit of tobacco chewing since childhood, and he also had a history of alcoholism for 20 years. On clinical examination, the patient was well oriented and average built. A nontender, nonfluctuant, firm to hard, fixed swelling was seen involving left angle of the mandible and left side of the neck. The right and left submandibular and cervical lymph nodes were palpable, enlarged, firm to hard in consistency, and fixed to the underlying tissues. Intraoral examination was not possible due to limited mouth opening. Orthopantomograph showed no radiographic evidence of any bone pathology. Considering the overall findings, the provisional diagnosis of cervical lymphadenopathy with unknown primary was made. The patient was referred for fine-needle aspiration cytology (FNAC) and ultrasonography. FNAC was suggestive of poorly differentiated carcinoma. Ultrasonography revealed evidence of heterogenous lobulated mass in superficial lobe of left parotid gland and left submandibular gland. Multiple enlarged lymph nodes of similar echotexture without hilum was noted along the left side of neck level IB, II, III, IV, and right level IB and IV. Ultrasonography was suggestive of neoplastic mass with bilateral metastatic lymph nodes. Since the ultrasonography could not give the exact location and the extent of the neoplastic mass, magnetic resonance imaging (MRI) was considered, and the patient was referred for the same.

Figure 1: Extraoral photograph showing swelling on left angle of mandible region and left side of neck

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Figure 2: Limited mouth opening

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MRI showed evidence of soft tissue mass with ill-defined borders involving the base and left half of anterior two-third of the tongue, floor of mouth, and adjacent part of the ramus of the mandible and left submandibular gland [Figure 3]. It was predominantly isointense to muscles on T1-weighted images, heterogenously hyperintense on T2-weighted images, and showed intense heterogenous post contrast enhancement. The lesion extended posterosuperiorly to involve left palatine tonsils, left lateral, and posterior wall of oropharynx and nasopharynx. It had eroded the left pterygoid plates, had infiltrated both pterygoid muscles and had displaced the left parapharyngeal space. Inferiorly, it had obliterated the left vallecula and left pyriform fossa and had pushed the uvula to the opposite side [Figure 4]. There was also evidence of an abnormal extensive lymph nodal mass on the left side, which was isointense on T1-weighted images, heterogeneously hyperintense on T2-weighted images with strong post contrast enhancement with some rounded hypointense areas within, suggestive of necrotic lymph nodes [Figure 5]. Superiorly, this lymph nodal mass was involving deep lobe and partly superficial lobe of the parotid gland; inferiorly it was involving the entire lymph node chain along the left internal jugular vein extending up to the cricoids cartilage. The left internal jugular vein and carotid artery were encased by this lymph nodal mass [Figure 6]. The patient was referred to the Tata Memorial Hospital for the treatment, but, unfortunately, the patient expired before his treatment could be completed.

Figure 3: T1-weighted (a), T2-weighted (b) and post contrast T1-weighted (c) axial image showing soft tissue mass with ill-defined borders involving the base and left half of anterior two-third of tongue, floor of mouth and adjacent part of the ramus of mandible and left parotid gland. The lesion is causing compression of oropharynx

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Figure 4: T2-weighted coronal image showing compression of oropharynx by malignant growth

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Figure 5: Post contrast T1-weighted coronal image showing extensive lymph nodal mass with few necrotic lymph nodes

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Figure 6: T1-weighted axial image showing encasement of left internal carotid artery by the malignant growth

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Discussion

Only 7% of oral cavity lesions are malignant, but of these lesions, squamous cell carcinoma (SCC) accounts for 90%. Other malignancies encountered in this region include minor salivary gland tumors (adenoid cystic carcinoma, adenocarcinoma, and mucoepidermoid carcinoma), lymphomas, and other rare tumors including sarcomas (liposarcoma, rhabdomyosarcoma), and a variety of common and uncommon neoplasms of the mandible. Most masses within the oral cavity, both benign and malignant, are amenable to direct clinical examination, which is the best means by which to detect mucosal involvement. ^[2] In the presented case, however, due to limited mouth opening intraoral examination was not possible. Morphologic imaging techniques are crucial in such cases. The highest sensitivity and optimal anatomic information of the tumor site are provided by MRI. ^[3] The superior soft tissue contrast and superb resolution of MRI make it the preferred technique for examining malignant lesions of the skull base, paranasal sinuses, nasopharynx, and oropharynx. The radiologist has two important goals in aiding decisions about therapy and management: To describe the tumor and to detect any pathologic adenopathy. Characteristics of the primary lesion that directly determine prognosis and aid in treatment planning include its epicenter or site of origin, size, presence of necrosis, invasion of adjacent structures, extension across the midline, involvement of bone or laryngeal cartilage, and status of the carotid artery or jugular vein. Clinically important nodal characteristics in the head and neck include the size, location, and number of metastatic ipsilateral and contralateral nodes to the primary lesion, presence or absence of necrosis, and extranodal spread with fixation to the adjacent structures. ^[4]

Nearly, all SCCa of the oral tongue occur on the ventrolateral surface of the tongue, and most of the lateral lesions arise from the middle and posterior one-third of the lateral oral tongue. These tumors typically invade the tongue musculature, spreading easily along the bundles of the intrinsic muscles deeper into the oral tongue or along extrinsic muscles to their sites of attachment (hyoid bone, mandible, styloid process, etc.) These tumors may also extend submucosally to involve the floor of the mouth, tonsils, mandible, and pharyngeal walls. Middle-third lateral lesions tend to invade the lateral floor of the mouth and mandible. Posterior third lateral lesions grow into the floor of the mouth and glossotonsillar sulcus, the oropharyngeal tonsil, and the underlying deep spaces. Lesions may extend superiorly to the soft palate through the palatoglossus muscle and from the soft palate to the nasopharynx through the veli palatini muscles. ^[5] In the presented case, the lesion extended posterosuperiorly to involve left palatine tonsils, left lateral, and posterior wall of oropharynx and nasopharynx. It had eroded the left pterygoid plates, had infiltrated both pterygoid muscles and had displaced the left parapharyngeal space. Inferiorly, it had obliterated the left vallecula and left pyriform fossa and had pushed the uvula to the opposite side. It was clear from the MRI that the cause of limited mouth opening was infiltration of both the pterygoid muscles.

The lymphatic drainage of oral tongue SCCa is primarily to submandibular and internal jugular nodes (levels I and II), often with bilateral involvement. ^[5] In the presented case, there was an abnormal extensive lymph nodal mass on the left side of the neck. It was isointense on T1-weighted images, heterogeneously hyperintense on T2-weighted images with strong post contrast enhancement with some rounded hypointense areas within, suggestive of necrotic lymph nodes. Superiorly, this lymph nodal mass was involving deep lobe and partly superficial lobe of the parotid gland; inferiorly it was involving the entire lymph node chain along the left internal jugular vein extending up to the cricoids cartilage. The left internal jugular vein and carotid artery were encased by this lymph nodal mass. The relationship of metastatic lymphadenopathy to the major vessels of the neck, particularly carotid artery, is an important consideration in determining surgical resectability. If more than 270° of the circumference of the carotid artery is surrounded by a tumor, it is considered "encased" and the tumor is generally surgically unresectable. ^[6],[7],[8] A delay in diagnosis or a failure to diagnose tongue cancer can have very serious consequences, including extreme weight loss, severe pain and discomfort, and in the most serious cases a shortened life expectancy. In the presented case, the lack of awareness of the patient about oral cancer in general and delay in seeking the medical help led to the termination of patient's life.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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